review of nerves and vessels of lower limb Flashcards
1
Q
what do spinal nerves C1-4 innervate
A
neck
2
Q
what do spinal nerves C5-T1 innervate
A
upper limb
3
Q
what to spinal nerves T2-L1 innervate
A
trunk
4
Q
what do spinal nerves L2-S3 innervate
A
lower limb
5
Q
what do spinal nerves S2-C1 innervate
A
perineum
6
Q
2 types of innervation
A
segmental (dermatomes), peripheral (nerves to muscles, cutaneous nerves)
7
Q
where do peripheral nerves to limbs emerge from
A
nerve plexuses
8
Q
define nerve plexus
A
formed when peripheral spinal nerve roots merge and split to produce a network of nerves from which new multi-segmental peripheral nerves emerge
9
Q
what plexus do nerves to lower limb emerge from
A
lumbo-sacral plexus
10
Q
what nerve supplies anterior compartment of thigh
A
femoral nerve (goes underneath inguinal ligament to femoral triangle); is a posterior division but supplies anteriorly (permanent pronation during development)
11
Q
what nerve supplies medial (adductor) compartment of thigh
A
obturator nerve (through obturator foramen in abdominal pelvis by pubic bone)
12
Q
what nerve supplies posterior compartment of thigh, leg, ankle and foot
A
sciatic nerve (or terminal branches tibial and common peroneal)
13
Q
general organisation of lumbo-sacral plexus
A
L2-S3; many terminal branches have supply from different spinal roots; roots -> trunks -> divisions -> cords -> terminal nerves
14
Q
before femoral nerve reaches anterior thigh, what does it give branches to
A
iliacus (hip flexor)
15
Q
what is a major landmark of the buttock in relation to nerves and vessels of gluteal region
A
piriformis (superior gluteal above, inferior gluteal below)
16
Q
what does the superior gluteal nerve supply
A
gluteus medius, gluteus minimus
17
Q
what does the inferior gluteal nerve supply
A
gluteus maximus
18
Q
what 2 other nerves emerge inferior to piriformis
A
sciatic nerve, posterior cutaneous nerve of thigh
19
Q
where does the sciatic nerve divide to give tibial and common peroneal nerves
A
just above knee (inconsistent)
20
Q
tibial nerve pathway
A
remains posterior and descends towards medial malleolus of ankle
21
Q
common peroneal nerve pathway
A
emerges from popliteal fossa and goes around laterally by the neck of the fibula, before dividing to give deep and superficial branches
22
Q
deep peroneal nerve pathway
A
remains anteriorly to supply anterior leg muscles
23
Q
superficial peroneal nerve pathway
A
supplies lateral compartment of leg
24
Q
what branch of the femoral nerve reaches the leg
A
saphenous nerve (cutaneous nerve of medial leg and foot)
25
what forms the sural nerve
branches of tibial and common peroneal (sural communicating branch from common peroneal)
26
what does the sural nerve supply
cutaneous nerve of lateral leg compartment and foot (sometimes removed for nerve reconstruction)
27
what does the tibial nerve divide into at the foot (supply all foot muscles between them)
lateral and medial plantar nerves
28
nerve and spinal nerve roots supplying iliopsoas and anterior thigh
femoral nerve (L2,3,4, posterior fibres), except iliopsoas which includes L1
29
nerve and spinal nerve roots supplying medial (adductor) compartment of thigh
obturator nerve (L2,3,4, anterior fibres)
30
nerve and spinal roots supplying posterior thigh, leg and foot
sciatic nerve (L3,4,5, S1,2,3, anterior and posterior fibres)
31
nerve and spinal roots supplying gluteus medius and minimus, and tensor fascia lata
superior gluteal nerve (L4,5, S1)
32
nerve and spinal roots supplying gluteus maximus
inferior gluteal nerve (L5, S1,2)
33
segmental motor supply: spinal nerves which contain motor nerve cell bodies for upper limb
C5-T1 (plexus)
34
segmental motor supply: spinal nerves which contain motor nerve cell bodies for lower limb
L2-S3 (plexus)
35
segmental motor supply: muscle function of anterior divisions
flexor
36
segmental motor supply: muscle function of posterior divisions
extensor
37
segmental motor supply: 4 principles of segmental supplies
muscles supplied by 2 adjacent spinal segments, same action on joint = same nerve supply, opposing muscles 1-2 segments above/below, more distal in limb = more caudal (inferior) in spine
38
segmental motor supply: spinal roots for hip flexion
L2,3
39
segmental motor supply: spinal roots for hip extension
L4,5
40
segmental motor supply: spinal roots for knee extension
L3,4
41
segmental motor supply: spinal roots for knee flexion
L5, S1
42
segmental motor supply: spinal roots for dorsiflexion (extension)
L4,5
43
segmental motor supply: spinal roots for plantarflexion (flexion)
S1,2
44
segmental motor supply: spinal root for foot inversion
L4
45
segmental motor supply: spinal roots for foot eversion
L5, S1
46
segmental motor supply: spinal roots for large toe extension
L5, S1
47
segmental motor supply: spinal roots for large toe flexion
S1,2
48
segmental nerve supply: define dermatome
sensation of field of body surface supplied by single spinal nerve
49
segmental nerve supply: dermatome supply to knee
anteriorly L2 to L3, posteriorly S1, S2, S3, S4, L1, L2, L3, L4, L5
50
segmental nerve supply: dermatome supply to foot (floor)
L4 to S2
51
what roots do fibres from posterior cutaneous nerve of thigh supply
S1, S2 (not all S1 and S2 fibres, but some)
52
segmental nerve supply: autonomous sensory zones
no overlap, so if abnormal sensation then indicative of spinal root damage
53
segmental nerve supply: L3 autonomous sensory zones
anterior and medial thigh
54
segmental nerve supply: L4 autonomous sensory zones
anterior thigh and knee
55
segmental nerve supply: S1 autonomous sensory zone
posterior lateral calf
56
segmental nerve supply: deep peroneal nerve autonomous sensory zone
cleft between large and second toe
57
cutaneous innervation of foot: dorsal nerves
saphenous (branch of femoral nerve), superficial and deep peroneal nerves, dorsal lateral cutaneous nerve of foot (termination of sural nerve), dorsal digital nerve (from deep fibular nerve)
58
cutaneous innervation of foot: plantar nerves
common plantar difical nerves, lateral plantar nerve, medial plantar nerve, proper plantar digital nerves, medial calcaneal branch
59
4 assessments of nerve function
motor, sensory, reflex, autonomic
60
example of assessment of nerve function: prolapsed intervertebral disc at L5/S1
motor - loss of eversion, sensory - loss of sensation of outer border of foot, reflex - loss of ankle jerk (S1), autonomic - minimal
61
example of assessment of nerve function: lesion of common peroneal nerve at fibular neck
motor - foot drop (lateral and anterior muscles of leg, losing ability to dorsiflex - high stepping/wide gait to avoid catching toes as they walk), sensory - loss of dorsum of foot at least, reflex - none, autonomic - minimal
62
arterial supply of lower limb
aorta -> common iliac -> external / internal iliac -> external passes under inguinal ligament to become femoral -> femoral -> [profunda femoris (deep) -> circumflex femoral (around hip)] -> anterior to posterior through hiatus of adductor magnus (potential occlusion) to become popliteal -> popliteal -> trifurcates after popliteal fossa: anterior tibial (-> dorsalis pedis), posterior tibial (-> plantar), peroneal
63
branch of internal iliac artery into thigh
obturator artery (passes through obturator foramen into thigh)
64
arteries where can feel pulse (ensure adequate perfusion)
femoral artery (cannulation), popliteal artery, posterior tibial artery, dorsalis pedis
65
femoral triangle boundaries
superior: inguinal ligament; medial: lateral edge of adductor longus; lateral: medial edge of sartorius
66
contents of femoral triangle (NAVY)
femoral nerve, artery, vein (also lymph nodes)
67
popliteal fossa boundaries
fascia, femur, medial and lateral heads of gastrocnemius, semimembranosus, biceps femoris
68
popliteal fossa contents
popliteal artery deeper than popliteal vein, tibial and common peroneal nerves, termination of small saphenous vein (into popliteal vein), lymph nodes
69
trifurcation of popliteal artery
anterior tibial first just after popliteal fossa, before carying on and dividing into peroneal and posterior tibial
70
arteries of ankle
anterior tibial (deep between bones, crossing ankle to become dorsalis pedis - pulse), posterior tibial (passes around lateral malleolus - take pulse)
71
feeling femoral artery in groin
between ASIS and pubic tubercle (press femoral artery against pubic ramus)
72
feeling dorsalis pedis artery
press against tarsals / metatarsals; between extensor hallicus lonus and tibialis anterior tendon
73
feeling posterior tibial artery
press against malleolus; between medial malleolus and calcaneal tendon
74
superficial venous drainage
dorsal venous arch -> long (emerges in front of and superior to medial malleolus, travelling up medial leg and thigh) / short (behind lateral malleolus and up posterior leg to pierce popliteal fossa fascia) saphenous veins -> perforating veins (drain from superficial to deep) -> short saphenous drains into popliteal vein at popliteal fossa, long saphenous drains into femoral vein at sapheno-femoral junction
75
deep venous drainage: what do they run alongside
run alongside arteries (often as venae comitantes)
76
deep venous drainage: what helps move blood
muscle pump in calf
77
deep venous drainage
anterior and posterior tibial veins -> popliteal vein (receives SSV) [and profunda femoris vein] -> femoral vein (arises at adductor canal; receives LSV) -> external iliac vein
78
what are venae comitantes
mutiple veins forming a network of smaller veins with arteries which they accomany, with connections between them
79
what do venae comitantes allow, and what promotes venous flow
allow heat exchange, with artery pulse promoting venous flow
80
what is a saphenous cut down
cut skin just above medial malleolus and find long saphenous vein, to inject fluids if hypotensive (shocked patient, advanced trauma life support)
81
what has superseded saphenous cut down
intraosseous administration of fluid (inserted into bone e.g. anterior tibia marrow space, with fluid infused into circulation)
82
consequence of sudden occlusion (arterial embolism)
acute ischaemia, intermittent claudication (muscle pain during activity in calf)
83
what is compartment syndrome
as neuromuscular compartments of limbs are enclosed in fibrous sheaths (e.g. fascia lata in thigh), they can be subjected to ischaemia by trauma-induced increased pressure
84
common compartments affected by compartment syndrome
anterior, posterior and lateral compartments of leg
85
can a pulse be felt in compartment syndrome
yes, as only need 50-60mmHg to collapse vessels (normally 25), despite ischaemia
86
what is trauma associated compartment syndrome
acute
87
what is exercise-induced compartment syndrome
chronic
88
acute compartment syndrome treatment
emergency fasciotomy to remove fascia and open compartment to relieve pressure
89
function of perforating veins
connect superficial and deep veins, allowing drainage from superficial to deep (as have valves)
90
what happens if valves in perforating veins are compromised (genetic, lifestyle etc.)
blood pushed from deep to superficial veins (varicose veins), leading to venous insufficiency
91
function of perforating veins
connect superficial and deep veins, allowing drainage from superficial to deep (as have valves)
92
what can varicose veins lead to
lipodermatosclerosis (skin thickening) and venous ulcers
93
what is the most important valve affected by varicose veins
sapheno-femoral junction valve
94
risk factor of DVT, and why
inactivity, as calf pump not working to pump against gravity (normally, contraction of muscles squeeze thin-walled veins and push blood up veins)
95
what are DVTs related to
pulmonary embolism (dislodge and goes to pulmonary circulation)
96
2 consequences of DVT
post-phlebitic syndrome, superficial thrombophlebitis
97
what helps prevent DVTs, and how
elastic surgical socks which compress superficial veins, promoting more vigorous deep venous return
98
2 consequences of DVT
post-phlebitic syndrome, superficial thrombophlebitis
99
what helps prevent DVTs, and how
elastic surgical socks which compress superficial veins, promoting more vigorous deep venous return
100
what are venous grafts used for
CABG (bypass between arteries), with valves in correct way to ensure flow in one direction
